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• zlib へ行く。
• zlib の差分を削除

#author("2024-08-30T03:45:49+00:00","default:yoya","yoya")
#author("2024-08-30T03:46:00+00:00","default:yoya","yoya")
TITLE:zlib (A Massively Spiffy Yet Delicately Unobtrusive Compression Library)
[[Compression]]

- http://www.zlib.net/ 
--  http://www.zlib.net/zlib_tech.html Technical Details

- http://oku.edu.mie-u.ac.jp/~okumura/compression/zlib.html zlib 入門
- http://dencha.ojaru.jp/programs/pg_filer_04_extra_03.html zlib1.2.2 FAQ 訳 
- http://www.futomi.com/lecture/japanese/rfc1950.html RFC 1950 ZLIB Compressed Data Format Specification version 3.3 日本語訳

- [[Deflate]] (圧縮アルゴリズム)

* 実装 [#r039a549]

- http://www.zlib.net/ # zlib
--   https://github.com/madler/zlib # adler32のひと
- https://github.com/jtkukunas/zlib # Intel
- https://github.com/cloudflare/zlib # CloudFlare
- https://github.com/ebiggers/libdeflate # Libdeflate
- https://github.com/zlib-ng/zlib-ng # zlib-ng
- https://github.com/simonis/zlib-chromium # zlib-chromium

- [[zlib-rs]]
- [[zlib-rs]] (Rust)

** 比較 [#compare]

- A comparison of Zlib implementations
--  http://www.htslib.org/benchmarks/zlib.html

- Improving zlib-cloudflare and comparing performance with other zlib forks
--  https://aws.amazon.com/jp/blogs/opensource/improving-zlib-cloudflare-and-comparing-performance-with-other-zlib-forks/

* compress / uncompress [#comp_uncomp]
** compress [#compress]

 compsize = ～; // 圧縮後のサイズより大きな値
 compbuff = malloc(compsize);
 int result = compress(compbuff, &compsize, origbuff, origsize);
 if (result != Z_OK) {
     if (result == Z_MEM_ERROR) {
         fprintf(stderr, "compress: Z_MEM_ERROR: can't malloc\n");
     } else if (result == Z_BUF_ERROR) {
         fprintf(stderr, "compress: Z_BUF_ERROR: not enough buff size\n");
     }
     return 1; // FAILURE
 }

** uncompress [#uncompress]

 origsize = ～;  // 伸張後のサイズより大きな値
 origbuff = malloc(origsize);
 int result = uncompress(origbuff, &origsize, compbuff, compsize);
 if (result != Z_OK) {
     if (result == Z_MEM_ERROR) {
         fprintf(stderr, "uncompress: Z_MEM_ERROR: can't malloc\n");
     } else if (result == Z_BUF_ERROR) {
         fprintf(stderr, "uncompress: Z_BUF_ERROR: not enough buff size\n");
     }
     return 1; // FAILURE
 }

* inflate / defrate [#q681d972]

(予定)


* 発表スライド [#slide]
 未圧縮形式と固定ハフマン
-- http://www.slideshare.net/7shi/deflate

* 参考 [#ref]

- http://tools.ietf.org/rfc/rfc1950.pdf
- http://tools.ietf.org/rfc/rfc1951.pdf
- http://tools.ietf.org/rfc/rfc1952.pdf
- PNG Deflate/Inflate 圧縮
--  http://www.sutv.zaq.ne.jp/linuz/tks/PngSpec1.2/PNG-Compression.html

- Zlib Flush Modes
- https://www.bolet.org/~pornin/deflate-flush.html


-  カスタムハフマン (dynamic huffman)
-- http://d.hatena.ne.jp/n7shi/20110719/1311093479
-  Zlib (Deflate のコンテナ)
--  http://www.futomi.com/lecture/japanese/rfc1950.html
-  Deflate (圧縮の仕様
--  http://www.futomi.com/lecture/japanese/rfc1951.html)
- IO_Zlib 1.0.0 リリース (ハマりどころメモ)
--  http://d.hatena.ne.jp/yoya/20110726/io_zlib

- SWFバイナリ編集のススメ番外編 (zlib 伸張)
--  https://labs.gree.jp/blog/2012/01/4082/
--  https://labs.gree.jp/blog/2014/01/4530/

* 関連 [#rel]

- [[Deflate]]
- [[PNG]]
- [[IO_Zlib]]

- [[LZFSE]] (Apple の圧縮技術)